/*
 * jdcoefct.c
 *
 * Copyright (C) 1994-1995, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains the coefficient buffer controller for decompression.
 * This controller is the top level of the JPEG decompressor proper.
 * The coefficient buffer lies between entropy decoding and inverse-DCT steps.
 *
 * In buffered-image mode, this controller is the interface between
 * input-oriented processing and output-oriented processing.
 * Also, the input side (only) is used when reading a file for transcoding.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"

/* Block smoothing is only applicable for progressive JPEG, so: */
#ifndef D_PROGRESSIVE_SUPPORTED
#undef BLOCK_SMOOTHING_SUPPORTED
#endif

/* Private buffer controller object */

typedef struct
{
	struct jpeg_d_coef_controller pub;	/* public fields */

	/* These variables keep track of the current location of the input side. */
	/* cinfo->input_iMCU_row is also used for this. */
	JDIMENSION      MCU_ctr;	/* counts MCUs processed in current row */
	int             MCU_vert_offset;	/* counts MCU rows within iMCU row */
	int             MCU_rows_per_iMCU_row;	/* number of such rows needed */

	/* The output side's location is represented by cinfo->output_iMCU_row. */

	/* In single-pass modes, it's sufficient to buffer just one MCU.
	 * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks,
	 * and let the entropy decoder write into that workspace each time.
	 * (On 80x86, the workspace is FAR even though it's not really very big;
	 * this is to keep the module interfaces unchanged when a large coefficient
	 * buffer is necessary.)
	 * In multi-pass modes, this array points to the current MCU's blocks
	 * within the virtual arrays; it is used only by the input side.
	 */
	JBLOCKROW       MCU_buffer[D_MAX_BLOCKS_IN_MCU];

#ifdef D_MULTISCAN_FILES_SUPPORTED
	/* In multi-pass modes, we need a virtual block array for each component. */
	jvirt_barray_ptr whole_image[MAX_COMPONENTS];
#endif

#ifdef BLOCK_SMOOTHING_SUPPORTED
	/* When doing block smoothing, we latch coefficient Al values here */
	int            *coef_bits_latch;
#define SAVED_COEFS  6			/* we save coef_bits[0..5] */
#endif
} my_coef_controller;

typedef my_coef_controller *my_coef_ptr;

/* Forward declarations */
METHODDEF int   decompress_onepass JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));

#ifdef D_MULTISCAN_FILES_SUPPORTED
METHODDEF int   decompress_data JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
#endif
#ifdef BLOCK_SMOOTHING_SUPPORTED
LOCAL boolean smoothing_ok JPP((j_decompress_ptr cinfo));
METHODDEF int   decompress_smooth_data JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf));
#endif


LOCAL void start_iMCU_row(j_decompress_ptr cinfo)
/* Reset within-iMCU-row counters for a new row (input side) */
{
	my_coef_ptr     coef = (my_coef_ptr) cinfo->coef;

	/* In an interleaved scan, an MCU row is the same as an iMCU row.
	 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
	 * But at the bottom of the image, process only what's left.
	 */
	if(cinfo->comps_in_scan > 1)
	{
		coef->MCU_rows_per_iMCU_row = 1;
	}
	else
	{
		if(cinfo->input_iMCU_row < (cinfo->total_iMCU_rows - 1))
			coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
		else
			coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
	}

	coef->MCU_ctr = 0;
	coef->MCU_vert_offset = 0;
}


/*
 * Initialize for an input processing pass.
 */

METHODDEF void start_input_pass(j_decompress_ptr cinfo)
{
	cinfo->input_iMCU_row = 0;
	start_iMCU_row(cinfo);
}


/*
 * Initialize for an output processing pass.
 */

METHODDEF void start_output_pass(j_decompress_ptr cinfo)
{
#ifdef BLOCK_SMOOTHING_SUPPORTED
	my_coef_ptr     coef = (my_coef_ptr) cinfo->coef;

	/* If multipass, check to see whether to use block smoothing on this pass */
	if(coef->pub.coef_arrays != NULL)
	{
		if(cinfo->do_block_smoothing && smoothing_ok(cinfo))
			coef->pub.decompress_data = decompress_smooth_data;
		else
			coef->pub.decompress_data = decompress_data;
	}
#endif
	cinfo->output_iMCU_row = 0;
}


/*
 * Decompress and return some data in the single-pass case.
 * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
 * Input and output must run in lockstep since we have only a one-MCU buffer.
 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
 *
 * NB: output_buf contains a plane for each component in image.
 * For single pass, this is the same as the components in the scan.
 */

METHODDEF int decompress_onepass(j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
{
	my_coef_ptr     coef = (my_coef_ptr) cinfo->coef;
	JDIMENSION      MCU_col_num;	/* index of current MCU within row */
	JDIMENSION      last_MCU_col = cinfo->MCUs_per_row - 1;
	JDIMENSION      last_iMCU_row = cinfo->total_iMCU_rows - 1;
	int             blkn, ci, xindex, yindex, yoffset, useful_width;
	JSAMPARRAY      output_ptr;
	JDIMENSION      start_col, output_col;
	jpeg_component_info *compptr;
	inverse_DCT_method_ptr inverse_DCT;

	/* Loop to process as much as one whole iMCU row */
	for(yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; yoffset++)
	{
		for(MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col; MCU_col_num++)
		{
			/* Try to fetch an MCU.  Entropy decoder expects buffer to be zeroed. */
			jzero_far((void FAR *)coef->MCU_buffer[0], (size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK)));
			if(!(*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer))
			{
				/* Suspension forced; update state counters and exit */
				coef->MCU_vert_offset = yoffset;
				coef->MCU_ctr = MCU_col_num;
				return JPEG_SUSPENDED;
			}
			/* Determine where data should go in output_buf and do the IDCT thing.
			 * We skip dummy blocks at the right and bottom edges (but blkn gets
			 * incremented past them!).  Note the inner loop relies on having
			 * allocated the MCU_buffer[] blocks sequentially.
			 */
			blkn = 0;			/* index of current DCT block within MCU */
			for(ci = 0; ci < cinfo->comps_in_scan; ci++)
			{
				compptr = cinfo->cur_comp_info[ci];
				/* Don't bother to IDCT an uninteresting component. */
				if(!compptr->component_needed)
				{
					blkn += compptr->MCU_blocks;
					continue;
				}
				inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index];
				useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width : compptr->last_col_width;
				output_ptr = output_buf[ci] + yoffset * compptr->DCT_scaled_size;
				start_col = MCU_col_num * compptr->MCU_sample_width;
				for(yindex = 0; yindex < compptr->MCU_height; yindex++)
				{
					if(cinfo->input_iMCU_row < last_iMCU_row || yoffset + yindex < compptr->last_row_height)
					{
						output_col = start_col;
						for(xindex = 0; xindex < useful_width; xindex++)
						{
							(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) coef->MCU_buffer[blkn + xindex], output_ptr, output_col);
							output_col += compptr->DCT_scaled_size;
						}
					}
					blkn += compptr->MCU_width;
					output_ptr += compptr->DCT_scaled_size;
				}
			}
		}
		/* Completed an MCU row, but perhaps not an iMCU row */
		coef->MCU_ctr = 0;
	}
	/* Completed the iMCU row, advance counters for next one */
	cinfo->output_iMCU_row++;
	if(++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows)
	{
		start_iMCU_row(cinfo);
		return JPEG_ROW_COMPLETED;
	}
	/* Completed the scan */
	(*cinfo->inputctl->finish_input_pass) (cinfo);
	return JPEG_SCAN_COMPLETED;
}


/*
 * Dummy consume-input routine for single-pass operation.
 */

METHODDEF int dummy_consume_data(j_decompress_ptr cinfo)
{
	return JPEG_SUSPENDED;		/* Always indicate nothing was done */
}


#ifdef D_MULTISCAN_FILES_SUPPORTED

/*
 * Consume input data and store it in the full-image coefficient buffer.
 * We read as much as one fully interleaved MCU row ("iMCU" row) per call,
 * ie, v_samp_factor block rows for each component in the scan.
 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
 */

METHODDEF int consume_data(j_decompress_ptr cinfo)
{
	my_coef_ptr     coef = (my_coef_ptr) cinfo->coef;
	JDIMENSION      MCU_col_num;	/* index of current MCU within row */
	int             blkn, ci, xindex, yindex, yoffset;
	JDIMENSION      start_col;
	JBLOCKARRAY     buffer[MAX_COMPS_IN_SCAN];
	JBLOCKROW       buffer_ptr;
	jpeg_component_info *compptr;

	/* Align the virtual buffers for the components used in this scan. */
	for(ci = 0; ci < cinfo->comps_in_scan; ci++)
	{
		compptr = cinfo->cur_comp_info[ci];
		buffer[ci] = (*cinfo->mem->access_virt_barray)
			((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
			 cinfo->input_iMCU_row * compptr->v_samp_factor, (JDIMENSION) compptr->v_samp_factor, TRUE);
		/* Note: entropy decoder expects buffer to be zeroed,
		 * but this is handled automatically by the memory manager
		 * because we requested a pre-zeroed array.
		 */
	}

	/* Loop to process one whole iMCU row */
	for(yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; yoffset++)
	{
		for(MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row; MCU_col_num++)
		{
			/* Construct list of pointers to DCT blocks belonging to this MCU */
			blkn = 0;			/* index of current DCT block within MCU */
			for(ci = 0; ci < cinfo->comps_in_scan; ci++)
			{
				compptr = cinfo->cur_comp_info[ci];
				start_col = MCU_col_num * compptr->MCU_width;
				for(yindex = 0; yindex < compptr->MCU_height; yindex++)
				{
					buffer_ptr = buffer[ci][yindex + yoffset] + start_col;
					for(xindex = 0; xindex < compptr->MCU_width; xindex++)
					{
						coef->MCU_buffer[blkn++] = buffer_ptr++;
					}
				}
			}
			/* Try to fetch the MCU. */
			if(!(*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer))
			{
				/* Suspension forced; update state counters and exit */
				coef->MCU_vert_offset = yoffset;
				coef->MCU_ctr = MCU_col_num;
				return JPEG_SUSPENDED;
			}
		}
		/* Completed an MCU row, but perhaps not an iMCU row */
		coef->MCU_ctr = 0;
	}
	/* Completed the iMCU row, advance counters for next one */
	if(++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows)
	{
		start_iMCU_row(cinfo);
		return JPEG_ROW_COMPLETED;
	}
	/* Completed the scan */
	(*cinfo->inputctl->finish_input_pass) (cinfo);
	return JPEG_SCAN_COMPLETED;
}


/*
 * Decompress and return some data in the multi-pass case.
 * Always attempts to emit one fully interleaved MCU row ("iMCU" row).
 * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED.
 *
 * NB: output_buf contains a plane for each component in image.
 */

METHODDEF int decompress_data(j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
{
	my_coef_ptr     coef = (my_coef_ptr) cinfo->coef;
	JDIMENSION      last_iMCU_row = cinfo->total_iMCU_rows - 1;
	JDIMENSION      block_num;
	int             ci, block_row, block_rows;
	JBLOCKARRAY     buffer;
	JBLOCKROW       buffer_ptr;
	JSAMPARRAY      output_ptr;
	JDIMENSION      output_col;
	jpeg_component_info *compptr;
	inverse_DCT_method_ptr inverse_DCT;

	/* Force some input to be done if we are getting ahead of the input. */
	while(cinfo->input_scan_number < cinfo->output_scan_number ||
		  (cinfo->input_scan_number == cinfo->output_scan_number && cinfo->input_iMCU_row <= cinfo->output_iMCU_row))
	{
		if((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
			return JPEG_SUSPENDED;
	}

	/* OK, output from the virtual arrays. */
	for(ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++)
	{
		/* Don't bother to IDCT an uninteresting component. */
		if(!compptr->component_needed)
			continue;
		/* Align the virtual buffer for this component. */
		buffer = (*cinfo->mem->access_virt_barray)
			((j_common_ptr) cinfo, coef->whole_image[ci],
			 cinfo->output_iMCU_row * compptr->v_samp_factor, (JDIMENSION) compptr->v_samp_factor, FALSE);
		/* Count non-dummy DCT block rows in this iMCU row. */
		if(cinfo->output_iMCU_row < last_iMCU_row)
			block_rows = compptr->v_samp_factor;
		else
		{
			/* NB: can't use last_row_height here; it is input-side-dependent! */
			block_rows = (int)(compptr->height_in_blocks % compptr->v_samp_factor);
			if(block_rows == 0)
				block_rows = compptr->v_samp_factor;
		}
		inverse_DCT = cinfo->idct->inverse_DCT[ci];
		output_ptr = output_buf[ci];
		/* Loop over all DCT blocks to be processed. */
		for(block_row = 0; block_row < block_rows; block_row++)
		{
			buffer_ptr = buffer[block_row];
			output_col = 0;
			for(block_num = 0; block_num < compptr->width_in_blocks; block_num++)
			{
				(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr, output_ptr, output_col);
				buffer_ptr++;
				output_col += compptr->DCT_scaled_size;
			}
			output_ptr += compptr->DCT_scaled_size;
		}
	}

	if(++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
		return JPEG_ROW_COMPLETED;
	return JPEG_SCAN_COMPLETED;
}

#endif							/* D_MULTISCAN_FILES_SUPPORTED */


#ifdef BLOCK_SMOOTHING_SUPPORTED

/*
 * This code applies interblock smoothing as described by section K.8
 * of the JPEG standard: the first 5 AC coefficients are estimated from
 * the DC values of a DCT block and its 8 neighboring blocks.
 * We apply smoothing only for progressive JPEG decoding, and only if
 * the coefficients it can estimate are not yet known to full precision.
 */

/*
 * Determine whether block smoothing is applicable and safe.
 * We also latch the current states of the coef_bits[] entries for the
 * AC coefficients; otherwise, if the input side of the decompressor
 * advances into a new scan, we might think the coefficients are known
 * more accurately than they really are.
 */

LOCAL           boolean smoothing_ok(j_decompress_ptr cinfo)
{
	my_coef_ptr     coef = (my_coef_ptr) cinfo->coef;
	boolean         smoothing_useful = FALSE;
	int             ci, coefi;
	jpeg_component_info *compptr;
	JQUANT_TBL     *qtable;
	int            *coef_bits;
	int            *coef_bits_latch;

	if(!cinfo->progressive_mode || cinfo->coef_bits == NULL)
		return FALSE;

	/* Allocate latch area if not already done */
	if(coef->coef_bits_latch == NULL)
		coef->coef_bits_latch = (int *)
			(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, cinfo->num_components * (SAVED_COEFS * SIZEOF(int)));
	coef_bits_latch = coef->coef_bits_latch;

	for(ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++)
	{
		/* All components' quantization values must already be latched. */
		if((qtable = compptr->quant_table) == NULL)
			return FALSE;
		/* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */
		for(coefi = 0; coefi <= 5; coefi++)
		{
			if(qtable->quantval[coefi] == 0)
				return FALSE;
		}
		/* DC values must be at least partly known for all components. */
		coef_bits = cinfo->coef_bits[ci];
		if(coef_bits[0] < 0)
			return FALSE;
		/* Block smoothing is helpful if some AC coefficients remain inaccurate. */
		for(coefi = 1; coefi <= 5; coefi++)
		{
			coef_bits_latch[coefi] = coef_bits[coefi];
			if(coef_bits[coefi] != 0)
				smoothing_useful = TRUE;
		}
		coef_bits_latch += SAVED_COEFS;
	}

	return smoothing_useful;
}


/*
 * Variant of decompress_data for use when doing block smoothing.
 */

METHODDEF int decompress_smooth_data(j_decompress_ptr cinfo, JSAMPIMAGE output_buf)
{
	my_coef_ptr     coef = (my_coef_ptr) cinfo->coef;
	JDIMENSION      last_iMCU_row = cinfo->total_iMCU_rows - 1;
	JDIMENSION      block_num, last_block_column;
	int             ci, block_row, block_rows, access_rows;
	JBLOCKARRAY     buffer;
	JBLOCKROW       buffer_ptr, prev_block_row, next_block_row;
	JSAMPARRAY      output_ptr;
	JDIMENSION      output_col;
	jpeg_component_info *compptr;
	inverse_DCT_method_ptr inverse_DCT;
	boolean         first_row, last_row;
	JBLOCK          workspace;
	int            *coef_bits;
	JQUANT_TBL     *quanttbl;
	INT32           Q00, Q01, Q02, Q10, Q11, Q20, num;
	int             DC1, DC2, DC3, DC4, DC5, DC6, DC7, DC8, DC9;
	int             Al, pred;

	/* Force some input to be done if we are getting ahead of the input. */
	while(cinfo->input_scan_number <= cinfo->output_scan_number && !cinfo->inputctl->eoi_reached)
	{
		if(cinfo->input_scan_number == cinfo->output_scan_number)
		{
			/* If input is working on current scan, we ordinarily want it to
			 * have completed the current row.  But if input scan is DC,
			 * we want it to keep one row ahead so that next block row's DC
			 * values are up to date.
			 */
			JDIMENSION      delta = (cinfo->Ss == 0) ? 1 : 0;

			if(cinfo->input_iMCU_row > cinfo->output_iMCU_row + delta)
				break;
		}
		if((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
			return JPEG_SUSPENDED;
	}

	/* OK, output from the virtual arrays. */
	for(ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++)
	{
		/* Don't bother to IDCT an uninteresting component. */
		if(!compptr->component_needed)
			continue;
		/* Count non-dummy DCT block rows in this iMCU row. */
		if(cinfo->output_iMCU_row < last_iMCU_row)
		{
			block_rows = compptr->v_samp_factor;
			access_rows = block_rows * 2;	/* this and next iMCU row */
			last_row = FALSE;
		}
		else
		{
			/* NB: can't use last_row_height here; it is input-side-dependent! */
			block_rows = (int)(compptr->height_in_blocks % compptr->v_samp_factor);
			if(block_rows == 0)
				block_rows = compptr->v_samp_factor;
			access_rows = block_rows;	/* this iMCU row only */
			last_row = TRUE;
		}
		/* Align the virtual buffer for this component. */
		if(cinfo->output_iMCU_row > 0)
		{
			access_rows += compptr->v_samp_factor;	/* prior iMCU row too */
			buffer = (*cinfo->mem->access_virt_barray)
				((j_common_ptr) cinfo, coef->whole_image[ci],
				 (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor, (JDIMENSION) access_rows, FALSE);
			buffer += compptr->v_samp_factor;	/* point to current iMCU row */
			first_row = FALSE;
		}
		else
		{
			buffer = (*cinfo->mem->access_virt_barray)
				((j_common_ptr) cinfo, coef->whole_image[ci], (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE);
			first_row = TRUE;
		}
		/* Fetch component-dependent info */
		coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS);
		quanttbl = compptr->quant_table;
		Q00 = quanttbl->quantval[0];
		Q01 = quanttbl->quantval[1];
		Q10 = quanttbl->quantval[2];
		Q20 = quanttbl->quantval[3];
		Q11 = quanttbl->quantval[4];
		Q02 = quanttbl->quantval[5];
		inverse_DCT = cinfo->idct->inverse_DCT[ci];
		output_ptr = output_buf[ci];
		/* Loop over all DCT blocks to be processed. */
		for(block_row = 0; block_row < block_rows; block_row++)
		{
			buffer_ptr = buffer[block_row];
			if(first_row && block_row == 0)
				prev_block_row = buffer_ptr;
			else
				prev_block_row = buffer[block_row - 1];
			if(last_row && block_row == block_rows - 1)
				next_block_row = buffer_ptr;
			else
				next_block_row = buffer[block_row + 1];
			/* We fetch the surrounding DC values using a sliding-register approach.
			 * Initialize all nine here so as to do the right thing on narrow pics.
			 */
			DC1 = DC2 = DC3 = (int)prev_block_row[0][0];
			DC4 = DC5 = DC6 = (int)buffer_ptr[0][0];
			DC7 = DC8 = DC9 = (int)next_block_row[0][0];
			output_col = 0;
			last_block_column = compptr->width_in_blocks - 1;
			for(block_num = 0; block_num <= last_block_column; block_num++)
			{
				/* Fetch current DCT block into workspace so we can modify it. */
				jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1);
				/* Update DC values */
				if(block_num < last_block_column)
				{
					DC3 = (int)prev_block_row[1][0];
					DC6 = (int)buffer_ptr[1][0];
					DC9 = (int)next_block_row[1][0];
				}
				/* Compute coefficient estimates per K.8.
				 * An estimate is applied only if coefficient is still zero,
				 * and is not known to be fully accurate.
				 */
				/* AC01 */
				if((Al = coef_bits[1]) != 0 && workspace[1] == 0)
				{
					num = 36 * Q00 * (DC4 - DC6);
					if(num >= 0)
					{
						pred = (int)(((Q01 << 7) + num) / (Q01 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
					}
					else
					{
						pred = (int)(((Q01 << 7) - num) / (Q01 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
						pred = -pred;
					}
					workspace[1] = (JCOEF) pred;
				}
				/* AC10 */
				if((Al = coef_bits[2]) != 0 && workspace[8] == 0)
				{
					num = 36 * Q00 * (DC2 - DC8);
					if(num >= 0)
					{
						pred = (int)(((Q10 << 7) + num) / (Q10 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
					}
					else
					{
						pred = (int)(((Q10 << 7) - num) / (Q10 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
						pred = -pred;
					}
					workspace[8] = (JCOEF) pred;
				}
				/* AC20 */
				if((Al = coef_bits[3]) != 0 && workspace[16] == 0)
				{
					num = 9 * Q00 * (DC2 + DC8 - 2 * DC5);
					if(num >= 0)
					{
						pred = (int)(((Q20 << 7) + num) / (Q20 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
					}
					else
					{
						pred = (int)(((Q20 << 7) - num) / (Q20 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
						pred = -pred;
					}
					workspace[16] = (JCOEF) pred;
				}
				/* AC11 */
				if((Al = coef_bits[4]) != 0 && workspace[9] == 0)
				{
					num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9);
					if(num >= 0)
					{
						pred = (int)(((Q11 << 7) + num) / (Q11 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
					}
					else
					{
						pred = (int)(((Q11 << 7) - num) / (Q11 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
						pred = -pred;
					}
					workspace[9] = (JCOEF) pred;
				}
				/* AC02 */
				if((Al = coef_bits[5]) != 0 && workspace[2] == 0)
				{
					num = 9 * Q00 * (DC4 + DC6 - 2 * DC5);
					if(num >= 0)
					{
						pred = (int)(((Q02 << 7) + num) / (Q02 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
					}
					else
					{
						pred = (int)(((Q02 << 7) - num) / (Q02 << 8));
						if(Al > 0 && pred >= (1 << Al))
							pred = (1 << Al) - 1;
						pred = -pred;
					}
					workspace[2] = (JCOEF) pred;
				}
				/* OK, do the IDCT */
				(*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace, output_ptr, output_col);
				/* Advance for next column */
				DC1 = DC2;
				DC2 = DC3;
				DC4 = DC5;
				DC5 = DC6;
				DC7 = DC8;
				DC8 = DC9;
				buffer_ptr++, prev_block_row++, next_block_row++;
				output_col += compptr->DCT_scaled_size;
			}
			output_ptr += compptr->DCT_scaled_size;
		}
	}

	if(++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows)
		return JPEG_ROW_COMPLETED;
	return JPEG_SCAN_COMPLETED;
}

#endif							/* BLOCK_SMOOTHING_SUPPORTED */


/*
 * Initialize coefficient buffer controller.
 */

GLOBAL void jinit_d_coef_controller(j_decompress_ptr cinfo, boolean need_full_buffer)
{
	my_coef_ptr     coef;

	coef = (my_coef_ptr) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(my_coef_controller));
	cinfo->coef = (struct jpeg_d_coef_controller *)coef;
	coef->pub.start_input_pass = start_input_pass;
	coef->pub.start_output_pass = start_output_pass;
#ifdef BLOCK_SMOOTHING_SUPPORTED
	coef->coef_bits_latch = NULL;
#endif

	/* Create the coefficient buffer. */
	if(need_full_buffer)
	{
#ifdef D_MULTISCAN_FILES_SUPPORTED
		/* Allocate a full-image virtual array for each component, */
		/* padded to a multiple of samp_factor DCT blocks in each direction. */
		/* Note we ask for a pre-zeroed array. */
		int             ci, access_rows;
		jpeg_component_info *compptr;

		for(ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++)
		{
			access_rows = compptr->v_samp_factor;
#ifdef BLOCK_SMOOTHING_SUPPORTED
			/* If block smoothing could be used, need a bigger window */
			if(cinfo->progressive_mode)
				access_rows *= 3;
#endif
			coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
				((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE,
				 (JDIMENSION) jround_up((long)compptr->width_in_blocks,
										(long)compptr->h_samp_factor),
				 (JDIMENSION) jround_up((long)compptr->height_in_blocks, (long)compptr->v_samp_factor), (JDIMENSION) access_rows);
		}
		coef->pub.consume_data = consume_data;
		coef->pub.decompress_data = decompress_data;
		coef->pub.coef_arrays = coef->whole_image;	/* link to virtual arrays */
#else
		ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
	}
	else
	{
		/* We only need a single-MCU buffer. */
		JBLOCKROW       buffer;
		int             i;

		buffer = (JBLOCKROW) (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
		for(i = 0; i < D_MAX_BLOCKS_IN_MCU; i++)
		{
			coef->MCU_buffer[i] = buffer + i;
		}
		coef->pub.consume_data = dummy_consume_data;
		coef->pub.decompress_data = decompress_onepass;
		coef->pub.coef_arrays = NULL;	/* flag for no virtual arrays */
	}
}
